Insert the missing words:

Systems are designed to process transactions and internal audit is concerned with controls that ensure the systems objectives are met. Where this does not happen, the system produces delinquent transactions that breach one or more of the five key control areas. An audit approach that ignores the systems but seeks to identify delinquent transactions may be seen as a . . . . . . . . . . . . . . . . . . . . . . . . . audit.

a. transactions-based

b. error-based

c. process-based

d. systems-based